Deflating and rolling up an iSUP after a paddle is definitely the easy bit compared to inflating it before a session. All boards will roll up slightly differently and some are easier than others. But without a doubt rolling up a board with a US box fin is the hardest. (A US box is a fin box that many of us have on our iSUPs and is very common on the more specialist SUPs such as race, touring and surf iSUPs) When rolling up a board with a US box it’s important to get the size of the roll/folds correct otherwise when your board is at the final roll/fold you may find your US fin box laying across it, putting a lot of strain on the PVC material and the fin box to fit it in the bag. And if you carry on packing up your iSUP like this session after session you may weaken your board and fin box over time.
The simple trick
Roll/fold your board like normal, but when you come to the end of the board fold the fin box section back in towards the board, before completing your last board fold. By doing this you will not only put less strain on the fin box and materials, but also always have a perfectly flat section of the board to put inside your bag and against your back when you are carrying it.